Bad Themometer... Bad Bad Themometer

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Memnoch

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Well, I guess I've learned my lesson on crappy digital thermometers...

Was at Williams Sonoma with the SWMBO a few weeks ago and decided to pick up a nice digital probe thermometer, $40 out of pocket.

The first time I used it was actually my first AG batch, been doing extract for a couple of years now, but was time to step up. Built out my MLT in a 10 gallon Home Depot cooler, works like a champ.

I figure out all my temps and water, and get the strike up to 164 degrees, according to the brand new thermometer. I am doing a batch sparge, sparge water is up to temp, everything seems to go without a hitch.

I check my gravities, they seem to be *way* off, but this being my first AG batch I didn't really know what they should have been at. Go through the boil, lots and lots of hops, Pliny the Elder clone that was on sale from Austin.

Boil is done, get down and start chilling it, normally takes 10-15 minutes or so to get it completely chilled, I'm going on 20 minutes... then 25 minutes, using the new digital thermometer. I run upstairs and grab ole' faithful, my restaurant thermometer that is probably 15 years old, but still works great. I calibrate it quickly in a glass of ice water, right at 32 degrees and get it down to the wort. Wort is now at 52 degrees, the digital is reading 85 degrees still, so really nice that the new digital thermometer was ~32 degrees off. The wonderful thing is that my mash would have been around 120 degrees.

Went ahead and carbed and bottled it, popped one open today, hop flavored water, very sad.

The only positive here is since I figured that it was trashed anyway, I only dry hopped about 1/3 of what was supposed to be dry hopped, so I saved some hops.

So the kicker... I take it back to Williams Sonoma, they give me a new one. I come home and check it in ice water, right around 32 degrees. Do another AG batch, although this time I am using two thermometers, by the end of the sparge, it's off again by 15 degrees. I'm not doing anything with it other than checking water temp, I'm not even leaving it in the MLT.

I guess word to the wise, always check your equipment, live and learn!
 
If you're using a probe thermometer, they tend to go nuts and read incorrectly if the wire gets wet. I've seen a number of people around here report that problem. There's a how-to for water proofing the probe with silicone tubing somewhere around here.

Here it is: Remote probe thermometer wort proofing

Otherwise, the cheap ($10) instant read thermometers work nice for taking quick measurements at the beginning of the mash and after infusions...
https://www.homebrewtalk.com/f11/remote-probe-thermometer-wort-proofing-26905/
 
Great, thanks for the info, dunno how I missed that thread...

I think I'll just stick with a cheap instant read until I get a better MLT with built-in's ;-)
 
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